Fractionation of butter oil into fractions with different physical and chemical properties is a possible solution for the problem of the excess of butter oil in the international market. With the objective of modeling the phase equilibria, the 1331 triglycerides were grouped into 14 families according to the number of carbons. Components belonging to the same family are considered to exhibit similar behavior when exposed to supercritical carbon dioxide (SC CO2). Using the Peng-Robinson equation of state, phase equilibrium calculations were performed for the butter oil/CO2 system with the oil represented by 14 components, the family groups. Correlations for the critical temperature and pressure as well as for the binary interaction parameters between CO2 and group families were developed. The model was able to successfully correlate the equilibrium solubility data obtained from the literature. Phase equilibrium predictions were found to be in excellent agreement with our data on the butter oil/CO2 system. The procedure shown should apply to other supercritical extraction systems involving triglyceride containing mixtures obtained from other sources.
Thermodynamic Modeling; Equation of State; Supercritical Carbon Dioxide; Fractionation; Butter Oil; Triglycerides
